Whoops! looks like i forgot this last step. The old forum's registration have been disabled.
I noticed it when I saw this user had his account created on January 2nd, when i had already disabled everything on the 1st of January .... ?
The user in question https://autohotkey.com/board/user/48867-mynameismax/ (login may be required)

@hoppfrosch
Good news and bad news...
We can now rename GitHub orgs quite easily. However, in the original GitHub AutoHotkey org, I am only a member and I don't have owner access. Therefore, the name AutoHotkey is forever reserved unless poly gives me owner access... :/

You can ask P if he is willing to transfer it - if there is no response you could try to contact GitHub and ask if they can assist. If you make the request on the behalf of the AutoHotkey Foundation they might be willing to help.

Not sure if this is the right place- but the login for archived forums doesn't work for new users. Guess that makes sense, but cool how it is setup.
As a matter of interest what are the permissions if one is able to login there?